MRI Physics And Instrumentation
Questions And Answers 100% Correct
Immediately after an initial 90 degree radio-frequency pulse is turned off, the hydrogen protons
will begin to: - Correct Answer-Dephase.
The introduction of gadolinium based contrast enhancement agents by Intra-venous injection
can involve passing through an abnormal blood brain barrier. The tissue compartments involved
are the: - Correct Answer-Intravascular to interstitial.
Once in the main magnetic field, a majority of hydrogen protons will align themselves - Correct
Answer-Parallel to Bo.
An equation derived to predict the MR signal intensity of a particular tissue as the result of a
Spin-echo pulse sequence is the: - Correct Answer-Bloch equation.
The tissue characteristic which depends more on the state (solid, liquid, gas)of a tissue than any
other factor is: - Correct Answer-T2 effects.
The effects of main magnetic field inhomogeneities on the FID signal are corrected for in a Spin-
echo sequence by applying a second radio-frequency pulse. The flip angle of this radio-
frequency pulse is: - Correct Answer-180 degrees
In MR imaging, for a chemical substance to be affected by the main magnetic field and the
radio-wave it must contain an - Correct Answer-Odd number of total protons and neutrons
What is the gyro-magnetic ratio of hydrogen? - Correct Answer-42.58 MHz.
, The Larmor frequency of hydrogen protons in a 1.5 Tesla magnetic field is: - Correct Answer-
63.9 MHz/Tesla
Which statement is true of the relaxation process? - Correct Answer-T2*(star) effects have no
effect on T2 decay
T2 is the measurement of time for the transverse component of the net magnetization vector to
decrease what percentage of its maximum value after the application of a 90 degree radio-
frequency pulse: - Correct Answer-37%.
Different tissues that have signals that appear similar on an MR image are described as - Correct
Answer-Isointense
Magnetic susceptibility is defined as the - Correct Answer-Tendency of a substance to attract or
repel magnetic lines of force which is decided by the magnetic properties of its electrons
T1 is the measurement of time for the longitudinal component of the net magnetization vector
to recover what percentage of its original value after the application of a 90 degree radio-
frequency pulse? - Correct Answer-63%.
The tissue characteristic that is dependent on the strength of the main magnetic field and
temperature is: - Correct Answer-T1 effects.
A 90 degree radio-frequency pulse will alter the net magnetization vector. Another effect is: -
Correct Answer-The hydrogen protons will have phase coherence
Which type of electromagnetic coils correct inhomogeneities in the main magnetic field? -
Correct Answer-shim coils
Questions And Answers 100% Correct
Immediately after an initial 90 degree radio-frequency pulse is turned off, the hydrogen protons
will begin to: - Correct Answer-Dephase.
The introduction of gadolinium based contrast enhancement agents by Intra-venous injection
can involve passing through an abnormal blood brain barrier. The tissue compartments involved
are the: - Correct Answer-Intravascular to interstitial.
Once in the main magnetic field, a majority of hydrogen protons will align themselves - Correct
Answer-Parallel to Bo.
An equation derived to predict the MR signal intensity of a particular tissue as the result of a
Spin-echo pulse sequence is the: - Correct Answer-Bloch equation.
The tissue characteristic which depends more on the state (solid, liquid, gas)of a tissue than any
other factor is: - Correct Answer-T2 effects.
The effects of main magnetic field inhomogeneities on the FID signal are corrected for in a Spin-
echo sequence by applying a second radio-frequency pulse. The flip angle of this radio-
frequency pulse is: - Correct Answer-180 degrees
In MR imaging, for a chemical substance to be affected by the main magnetic field and the
radio-wave it must contain an - Correct Answer-Odd number of total protons and neutrons
What is the gyro-magnetic ratio of hydrogen? - Correct Answer-42.58 MHz.
, The Larmor frequency of hydrogen protons in a 1.5 Tesla magnetic field is: - Correct Answer-
63.9 MHz/Tesla
Which statement is true of the relaxation process? - Correct Answer-T2*(star) effects have no
effect on T2 decay
T2 is the measurement of time for the transverse component of the net magnetization vector to
decrease what percentage of its maximum value after the application of a 90 degree radio-
frequency pulse: - Correct Answer-37%.
Different tissues that have signals that appear similar on an MR image are described as - Correct
Answer-Isointense
Magnetic susceptibility is defined as the - Correct Answer-Tendency of a substance to attract or
repel magnetic lines of force which is decided by the magnetic properties of its electrons
T1 is the measurement of time for the longitudinal component of the net magnetization vector
to recover what percentage of its original value after the application of a 90 degree radio-
frequency pulse? - Correct Answer-63%.
The tissue characteristic that is dependent on the strength of the main magnetic field and
temperature is: - Correct Answer-T1 effects.
A 90 degree radio-frequency pulse will alter the net magnetization vector. Another effect is: -
Correct Answer-The hydrogen protons will have phase coherence
Which type of electromagnetic coils correct inhomogeneities in the main magnetic field? -
Correct Answer-shim coils
